1. Field of the Invention
The present invention relates to an optical module including an optical device, an optical apparatus including an optical module, and a method for using an optical module.
2. Description of the Related Art
Various optical apparatuses are used in optical communications systems, and some of those apparatuses comprise an optical device having a temperature-dependent characteristic. Such an apparatus has a thermo-module for adjusting the temperature of the optical device, and a control unit for controlling the thermo-module in order to keep the characteristic of the optical device constant.
This thermo-module includes two insulating plates and a plurality of peltier elements interposed therebetween. When an electric current is supplied in one direction to thermo-module, the temperature of one insulating plate rises and the temperature of the other insulating plate falls. On the contrary, when an electric current is supplied in an opposite direction, the temperature of the other insulating plate rises and the temperature of the one insulating plate falls. The optical device is fixed on the one insulating plate, for example with solder, so that it can be heated or cooled through the one insulating plate of the thermo-module.
However, sometimes it becomes impossible suddenly to obtain desired characteristics of the optical apparatus during the operation or, especially immediately after the apparatus is started up.